Water beds are comprised of a frame that carries a liquid filled envelope upon which persons recline. The frame includes a platform having the plan configuration desired, and upstanding side and end walls that confine the overlying mattress to said plan configuration. Flat plastic sheet is employed in the mattress construction, folded and/or seam welded together in a rectangular envelope formation with a fill opening adapted to be closed. The envelope is filled with a heavy liquid such as water, whereby a person reclining is supported by means of flotation as a result of displacement. In a basic water bed mattress as thus far described there is an absence of means to prevent wave motion, and as a result continued sloshing is a characteristic disadvantage which adversely affects a number of persons who cannot tolerate it. Heretofore, various arrangements of surge controlling baffles have been proposed, but with complexity and at considerable expense. Therefore, it is a general object of this invention to damp out wave motion in liquid filled mattresses, without resort to the complexities of the prior art baffles attached to the mattress envelope.
Flotation mattresses of the type here under consideration have been made with various forms and types of baffles, incorporated therein and attached to the outside envelope, all of plastic materials, and designed to reduce wave motion by means of compartmenting and flow restriction therethrough. The multiplicity of compartments and their attachment to the outside envelope becomes complicated and costly, it being an object of this invention to provide a detached means which damps wave motion, all without fastening to the plastic walls of the mattress which heretofore was thought to be necessary. With the present invention, a detached motion damping means is positioned by flotation within the outside envelope, to carry depending curtains that impede wave motion.
It is the phenomenon of wave motion in heavy liquid such as water with which the present invention is primarily concerned. In practice, when a person applies his or her weight onto the top surface of a water bed mattress, sudden displacement as is required by flotation of that person causes liquid motion with inertia from the position of that person, in the form of moving waves. These waves move horizontally and reflect from the side and end walls of the mattress which are backed by the hard structural retaining walls of the frame, and it is these waves which this invention hastens to dissipate and/or absorb. Accordingly, it is an object of this invention to reduce and to substantially eliminate the direct as well as reflective wave motion in liquid filled mattresses. To these ends, curtains depend from flotation members and within and between which bodies of liquid are entrapped and movement thereof restricted. Also, a thick fiber batting is carried by the flotation members and against which reflective wave motion is reduced.
The depth of water bed mattresses is predicated upon maximum anticipated weight of the persons to be supported thereby, and eight and one half (81/2) inches is the norm or depth of such a mattress. However, there are occasions when the top panel of the mattress will bottom out upon the bottom panel, and to this end it is an object of this invention to provide the aforesaid thick fiber batting that presents a coextensive pad that prevents and/or cushions bottoming.
The features hereinabove referred to are incorporated in a flotation unit comprised of shaping bars made of floatable material and to which the wave controlling curtains and fiber batting are attached. The unit is free floating, constructed of polyvinylchloride, polyethylene and polyester plastic materials, and the like. It is an object to employ such materials that are durable, non degradable and resistant to age, and therefore reliable.